Storage system

ABSTRACT

A storage system includes a storage grid and a container lift. The container lift includes a lifting assembly suspended from a spoolable lifting elements and arranged to be raised/lowered in order to raise/lower an accompanying storage container within the storage grid. The lifting assembly includes a lifting frame part for releasable attachment to a storage container and a guide shuttle arranged to guide the lifting frame part and any accompanying storage container as the lifting frame part is raised and lowered within the storage grid. The guide shuttle is arranged above the lifting frame part and includes guide elements arranged to stabilise and maintain horizontal alignment of the lifting frame part and any accompanying storage container. The framework features internal guide surfaces arranged to stabilise and maintain the horizontal alignment of the lifting frame part, when the guide shuttle is at a level above the top rail grid.

TECHNICAL FIELD

The present invention relates to an automated storage system, acontainer lift vehicle for use in such storage systems, as well asmethods for use of the storage system.

BACKGROUND

FIGS. 1A and 2B disclose a typical prior art automated storage andretrieval system 1 with a framework structure 100. FIGS. 1B and 2Bdisclose prior art container handling vehicles 200,300 operating in thesystem 1 disclosed in FIGS. 1A and 2A, respectively.

The framework structure 100 defines a storage grid 104 comprising aplurality of upright members 102 and optionally a plurality ofhorizontal members 103 supporting the upright members 102. The members102, 103 may typically be made of metal, e.g. extruded aluminiumprofiles.

The storage grid 104 comprises multiple grid columns 112. A largemajority of the grid columns are also termed storage columns 105, inwhich storage containers 106, also known as bins, are stacked one on topof another to form stacks 107.

Each storage container 106 may typically hold a plurality of productitems (not shown), and the product items within a storage container 106may be identical or may be of different product types depending on theapplication.

The grid columns 112 of the storage grid 104 guard against horizontalmovement of the of storage containers 106 in the stacks 107, and guidesvertical movement of the containers 106, but does normally not otherwisesupport the storage containers 106 when stacked. A cross-sectional viewof an upright member 102 of the storage grid 104 is shown in FIG. 3. Theupright member 102 comprises vertical guide surfaces 116 (or verticalguide plates) for guiding a storage container being moved inside a gridcolumn 112. In a grid column, each of the four upright members 102provides an inside corner 117 for guiding a corresponding corner of astorage container 106, see FIG. 4 showing the cross-section of a gridcolumn 112 and the schematic circumference of a storage container 106.Typically, each upright member features eight vertical guide surfaces116 and may thus provide an inside corner 117 of four separate gridcolumns 112 of the storage grid 104.

The automated storage and retrieval system 1 comprises a rail system 108(or a top rail grid) arranged in a grid pattern across the top of thestorage grid 104, on which rail system 108 a plurality of containerhandling vehicles 200,300 (as exemplified in FIGS. 1B and 2B) areoperated to raise storage containers 106 from, and lower storagecontainers 106 into, the storage columns 105, and also to transport thestorage containers 106 above the storage columns 105. The horizontalextent of one of the grid cells 122 constituting the grid pattern is inFIGS. 1A and 2A marked by thick lines.

Each grid cell 122 has a width which is typically within the interval of30 to 150 cm, and a length which is typically within the interval of 50to 200 cm. Each grid opening 115 has a width and a length which istypically 2 to 10 cm less than the width and the length of the grid cell122 due to the horizontal extent of the rails 110,111.

The rail system 108 comprises a first set of parallel rails 110 arrangedto guide movement of the container handling vehicles 200,300 in a firstdirection X across the top of the frame structure 100, and a second setof parallel rails 111 arranged perpendicular to the first set of rails110 to guide movement of the container handling vehicles 200,300 in asecond direction Y which is perpendicular to the first direction X. Inthis way, the rail system 108 defines the upper ends of the grid columns112 above which the container handling vehicles 200,300 can movelaterally, i.e. in a plane which is parallel to the horizontal X-Yplane. Commonly, at least one of the sets of rails 110,111 is made up ofdual-track rails allowing two container handling vehicles to pass eachother on neighbouring grid cells 122. Dual-track rails are well-knownand disclosed in for instance WO 2015/193278 A1 and WO 2015/140216 A1,the contents of which are incorporated herein by reference.

Each prior art container handling vehicle 200,300 comprises a vehiclebody and a wheel arrangement of eight wheels 201,301, wherein a firstset of four wheels 32 a enable the lateral movement of the containerhandling vehicles 200,300 in the X direction and a second set of fourwheels 32 b enable the lateral movement in the Y direction. One or bothsets of wheels in the wheel arrangement can be lifted and lowered, sothat the first set of wheels and/or the second set of wheels can beengaged with the respective set of rails 110, 111 at any one time.

Each prior art container handling vehicle 200,300 also comprises alifting device 18 (only shown in FIG. 2B) for vertical transportation ofstorage containers 106, e.g. raising a storage container 106 from, andlowering a storage container 106 into, a grid column 112. The liftingdevice 18 comprises four metal lifting bands 16 extending in a verticaldirection and connected close to the corners of a lifting frame 17 (mayalso be termed a gripping device) such that the lifting frame is kepthorizontal. The lifting frame 17 features container connecting elements24 for releasable connection to a storage container, and guiding pins30. The lateral movement of the lifting frame 17 is restricted by theupright members 102 defining a grid column 112 when the lifting frame 17moves vertically within the column.

To raise or lower the lifting frame 17 (and optionally a connectedstorage container 6), the lifting bands 16 are connected to a band driveassembly (not shown). In the band drive assembly, the lifting bands 16are commonly spooled on/off at least two rotating lifting shafts orreels arranged in the container-handling vehicle, wherein the liftingshafts are further connected via belts/chains to at least one commonrotor shaft providing synchronized rotational movement to the at leasttwo lifting shafts. Various designs of the lifting shafts are describedin for instance WO2015/193278 A1 and PCT/EP2017/050195. Since thelifting bands 16 are spooled off/on a shaft or reel when the liftingframe 17 is lowered/lifted, minor variations in the thickness of thelifting bands 16 will cause corresponding differences in the distancebetween the shaft/reel and each corner of the lifting frame 16. Suchminor variations in the thickness are unavoidable, and the subsequentdifferences in the distance between the shaft/reel and each corner ofthe lifting frame will increase when the length of the lifting bands,and consequently the maximum lifting height of the lifting device, isincreased. When the differences in the distance between the shaft/reeland each corner of the lifting frame 17 increases, the possible tilt ofthe lifting frame will also increase. During vertical movement within agrid column 112, the lifting frame 17 must be kept substantiallyhorizontal to avoid having the lifting frame and/or a connected storagecontainer from becoming stuck within the column. Consequently, theuseful lifting height of the lifting device is restricted due to therequirement of keeping the lifting frame substantially horizontal whenused to transfer a storage container 106 inside a grid column 112. Theuseful lifting height of the prior art container handling vehicles200,300 is commonly about 6 meters, which corresponds to the height ofthe prior art storage grids 104.

Conventionally, and also for the purpose of this application, Z=1identifies the uppermost layer of the storage grid 104, i.e. the layerimmediately below the rail system 108, Z=2 the second layer below therail system 108, Z=3 the third layer etc. In the prior art storage griddisclosed in FIGS. 1A and 2A, Z=8 identifies the lowermost, bottom layerof the storage grid 104. Consequently, as an example, and using theCartesian coordinate system X, Y, Z indicated in FIGS. 1A and 2B, thestorage container identified as 106′ in FIG. 1 can be said to occupygrid location or cell X=10, Y=2, Z=3. The container handling vehicles200,300 can be said to travel in layer Z=0 and each grid column can beidentified by its X and Y coordinates.

Each container handling vehicle 200 comprises a storage compartment orspace (not shown) for receiving and stowing a storage container 106 whentransporting the storage container 106 across the top of the storagegrid 104. The storage space may comprise a cavity arranged centrallywithin the vehicle body, e.g. as is described in WO2014/090684A1, thecontents of which are incorporated herein by reference.

Alternatively, the container handling vehicles 300 may have a cantileverconstruction as described in NO317366, the contents of which are alsoincorporated herein by reference.

The container handling vehicles 200 may have a footprint, i.e. an extentin the X and Y directions, which is generally equal to the horizontalarea of a grid cell 122, i.e. the extent of a grid cell 122 in the X andY directions, e.g. as is described in WO2015/193278A1, the contents ofwhich are incorporated herein by reference.

Alternatively, the container handling vehicles 200 may have a footprintwhich is larger than the horizontal area of a grid cell 122, e.g. as isdisclosed in WO2014/090684A1.

In a storage grid 104, most of the grid columns 112 are storage columns105, i.e. grid columns wherein storage containers 106 are stored instacks 107. However, a storage grid 104 normally has at least one gridcolumn 112 which is not used for storing storage containers 106, but isarranged at a location wherein the container handling vehicles 200,300can drop off and/or pick up storage containers 106 so that they can betransported to a second location (not shown) where the storagecontainers 106 can be accessed from outside of the storage grid 104 ortransferred out of or into the grid 104. Within the art, such a locationis normally referred to as a “port” and the grid column 112 at which theport is located may be referred to as a transfer column 119,120. Thedrop-off and pick-up ports are the upper ends/openings of a respectivetransfer column 119,120.

The prior art storage grids 104 in FIGS. 1A and 2A comprise two transfercolumns 119 and 120. The first transfer column 119 may for examplecomprise a dedicated drop-off port where the container handling vehicles200,300 can drop off storage containers 106 to be transported throughthe transfer column 119 and further to e.g. a picking/stocking station,and the second transfer column 120 may comprise a dedicated pick-up portwhere the container handling vehicles 200,300 can pick up storagecontainers 106 that have been transported through the transfer column120 from e.g. a picking/stocking station. A storage container may betransported through a transfer column by use of the lifting device of acontainer handling vehicle 200,300 or by use of a storage container liftarranged in the transfer column. Each of the ports of the first andsecond transfer column may be suitable for both pick-up and drop-off ofstorage containers.

The second location may typically be a picking/stocking station, whereinproduct items are removed from and/or positioned into the storagecontainers 106. In a picking/stocking station, the storage containers106 are normally never removed from the automated storage and retrievalsystem 1 but are returned into the storage grid 104 once accessed.

For monitoring and controlling the automated storage and retrievalsystem 1, e.g. monitoring and controlling the location of respectivestorage containers 106 within the storage grid 104; the content of eachstorage container 106; and the movement of the container handlingvehicles 200,300 so that a desired storage container 106 can bedelivered to the desired location at the desired time without thecontainer handling vehicles 200,300 colliding with each other, theautomated storage and retrieval system 1 comprises a computerizedcontrol system (not shown) which typically comprises a database forkeeping track of the storage containers 106.

A conveyor system comprising conveyor belts or rollers is commonlyemployed to transport the storage containers from a lower end of thetransfer columns 119,120 to e.g. a picking/stocking station.

A conveyor system may also be arranged to transfer storage containersbetween different storage grids, e.g. as is described inWO2014/075937A1, the contents of which are incorporated herein byreference.

Further, WO2016/198467A1, the contents of which are incorporated hereinby reference, discloses an example of a prior art access system havingconveyor belts (FIGS. 5a and 5b in WO2016/198467A1) and a frame mountedrail (FIGS. 6a and 6b in WO2016/198467A1) for transporting storagecontainers between transfer columns and stations where operators canaccess the storage containers.

When a storage container 106 stored in the storage grid 104 disclosed inFIG. 1A is to be accessed, one of the container handling vehicles200,300 is instructed to retrieve the target storage container 106 fromits position in the storage grid 104 and transport it to or through thetransfer column 119. This operation involves moving the containerhandling vehicle 200,300 to a grid location above the storage column 105in which the target storage container 106 is positioned, retrieving thestorage container 106 from the storage column 105 using the containerhandling vehicle's lifting device (not shown), and transporting thestorage container 106 to the transfer column 119. If the target storagecontainer 106 is located deep within a stack 107, i.e. with one or aplurality of other storage containers positioned above the targetstorage container 106, the operation also involves temporarily movingthe above-positioned storage containers prior to lifting the targetstorage container 106 from the storage column 105. This step, which issometimes referred to as “digging” within the art, may be performed withthe same container handling vehicle 200,300 that is subsequently usedfor transporting the target storage container 106 to the transfercolumn, or with one or a plurality of other cooperating containerhandling vehicles 200,300. Alternatively, or in addition, the automatedstorage and retrieval system 1 may have container handling vehicles200,300 specifically dedicated to the task of temporarily removingstorage containers 106 from a storage column 105. Once the targetstorage container 106 has been removed from the storage column 105, thetemporarily removed storage containers can be repositioned into theoriginal storage column 105. However, the removed storage containers mayalternatively be relocated to other storage columns 105.

When a storage container 106 is to be stored in the grid 104, one of thecontainer handling vehicles 200,300 is instructed to pick up the storagecontainer 106 from the transfer column 120 and to transport it to a gridlocation above the storage column 105 where it is to be stored. Afterany storage containers positioned at or above the target position withinthe storage column stack 107 have been removed, the container handlingvehicle 200,300 positions the storage container 106 at the desiredposition. The removed storage containers may then be lowered back intothe storage column 105 or relocated to other storage columns 105.

WO 2014/075937 A1 discloses a prior art storage system comprising twoseparate storage grids 104′ ,104″arranged vertically above each other,see FIG. 5. Each storage grid is arranged on an intermediate floor 80′,80″ (i.e. a mezzanine). The two storage grids and a plurality ofpicking/stocking stations 109 are interconnected by storage containerlifts 50 arranged to transport a storage container between the storagegrids and/or between any of the storage grids and a picking/stockingstation. The container handling vehicles 300 arranged at the top railgrids 108′,108″ of the storage grids comprises a lifting device 18 whichis unable to lift or lower a storage container over a vertical distancelarger than the height of a single storage grid, see description above.The lifting devices 18 of the container handling vehicles 300 are notable to lift/lower a storage container 106 a vertical distance exceedingthe height of a single storage grid which is about 6 m. Thus, thestorage container lifts 50 are a requirement in these prior art systemsto allow transport of a storage container 106 between the two storagegrids 104′,104″or between a storage grid 104′ and one of thepicking/stocking stations 109.

The major components of a prior art storage container lift 50 are shownin FIG. 6. The storage container lift features two parallel and verticalguide members 51, each featuring a guide track 52, and a storagecontainer shuttle 53. The storage container shuttle 53 features twosupport arms 54 upon which a storage container 106 may be arranged and avertical guide frame 55 featuring guide wheels 56 arranged in thecorresponding guide tracks of the guide members 51. The storagecontainer shuttle may be moved vertically by appropriate lifting meansnot disclosed. The storage container lift is arranged within a gridcolumn 112. The available horizontal area within a grid column (i.e. thearea not occupied by a storage container) is minimal, see FIG. 6, andthe requirement of arranging the vertical guide members within orbetween the grid columns means that the margin for errors in movement ofthe storage container shuttle is very low.

In view of the above, the aim of the present invention is to provide anautomated storage and retrieval system, and a method for operating sucha system, that solves or at least mitigates one or more of theaforementioned problems related to the use of prior art storage andretrieval systems.

SUMMARY OF THE INVENTION

The present invention is defined by the attached claims and in thefollowing:

In a first aspect, the present invention provides a storage systemcomprising at least one storage grid and a container lift, the storagegrid comprises vertical column profiles defining a plurality of gridcolumns, the grid columns comprise storage columns, in which storagecontainers can be stored one on top of another in vertical stacks, andat least one transfer column, each of the grid columns being defined byfour vertically extending column profiles, and the column profiles areinterconnected at their upper ends by top rails forming a horizontal toprail grid of the storage grid, wherein the container lift comprises

-   -   a lifting assembly which is suspended from one or more spoolable        lifting elements and arranged to be raised or lowered in order        to raise or lower an accompanying storage container within the        storage grid, wherein the lifting assembly comprises a lifting        frame part for releasable attachment to an upper section of a        storage container and a guide shuttle arranged to guide the        lifting frame part and any accompanying storage container as the        lifting frame part is raised and lowered within the storage        grid, the guide shuttle is arranged above the lifting frame part        and comprises guide elements which are each arranged to interact        with one of the four column profiles of a grid column to        stabilise and maintain horizontal alignment of the lifting frame        part and any accompanying storage container during the raising        and/or lowering of the lifting frame part; and    -   a framework featuring internal guide surfaces arranged to        interact with the guide elements of the guide shuttle when the        guide shuttle is at a level above the top rail grid, such that        the horizontal alignment of the lifting frame part is stabilised        and maintained.

In other words, the internal guide surfaces are arranged to interactwith the guide elements of the guide shuttle such that horizontalmisalignment of the lifting frame part is restricted.

In other words, each of the guide elements is arranged to interact withone of the four column profiles of a grid column to limit and/orrestrict horizontal misalignment of the lifting frame part and anyaccompanying storage container during the raising and/or lowering of thelifting frame part.

Moreover, each of the guide elements is arranged to interact with one ofthe four column profiles of a grid column to restrict tilting of thelifting frame part and any accompanying storage container, relative ahorizontal plane, during the raising and/or lowering of the liftingframe part.

In an embodiment of the storage system, the container lift may move inat least one lateral direction relative to the top rail grid.

In an embodiment of the storage system, the container lift may move intwo perpendicular lateral directions relative to the top rail grid.

In an embodiment of the storage system, the spoolable lifting elementsmay be selected from any suitable type of lifting band or wire.

In an embodiment of the storage system, the guide elements comprisesliding devices, roller assemblies or any combination thereof.

In an embodiment of the storage system, each column profile of a gridcolumn comprises two vertical guide surfaces forming an inside corner ofthe grid column, and each guide element is arranged to interact with atleast one of the vertical guide surfaces of a corresponding inner cornerof a grid column in which the lifting assembly is moved.

In an embodiment of the storage system, each guide element may comprisea sliding or rotatable surface arranged to interact with at least one ofthe vertical guide surfaces of a corresponding inner corner of a gridcolumn in which the lifting assembly is moved.

In an embodiment of the storage system, the guide elements are arrangedto interact with all the vertical guide surfaces of a grid column inwhich the lifting assembly is moved.

In an embodiment of the storage system, the guide elements are arrangedsuch that all the vertical guide surfaces of a grid column in which thelifting assembly is moved will interact with a guide element.

In an embodiment of the storage system, at least one of the guideelements comprises a roller assembly having at least one rotatablecircumference arranged to interact with a corresponding vertical guidesurface of a grid column in which the lifting assembly is moved.

In an embodiment of the storage system, the roller assembly comprises atleast one rotatable circumference arranged to interact with the verticalguide surfaces of a corresponding inside corner of a grid column inwhich the lifting frame part is moved.

In other words, the roller assembly may comprise at least one rotatablesurface.

In an embodiment of the storage system, the guide shuttle comprises fourvertically extended corner sections, wherein at least one guide elementis arranged at each corner section. The at least one guide element maycomprise two or more vertically separate contact points or a verticallyextended contact area, wherein the vertical separation of the contactpoints or the extension of the contact area is sufficient to restrictthe tilt of the lifting frame part relative a horizontal plane.

The contact points or the contact area may be a sliding or rotatablesurface.

In an embodiment of the storage system, the guide elements are arrangedto interact with all the vertical guide surfaces of a grid column (i.e.all of eight vertical guide surfaces) in which the lifting assembly ismoved.

In an embodiment of the storage system, each of the guide elements maycomprise two vertically separate contact points or a vertically extendedcontact area, wherein the vertical separation or extent is sufficient torestrict the tilt of the lifting frame relative a horizontal plane. Thevertical separation of the contact points, or the vertical extent of thecontact area, may be at least 25 times, at least 50 times or at least100 times the horizontal distance between the contact points, or thecontact area, and a corresponding vertical guide surface or inner guidesurface, or a corresponding internal guide surface of the containerlift.

In an embodiment of the storage system, the vertical separation of thecontact points, or the vertical extent of the contact area, may be atleast 25% or at least 50% of the width of the lifting frame part.

In an embodiment of the storage system, the container lift is acontainer lift vehicle comprising a vehicle body, into which a storagecontainer may be lifted by the lifting assembly, and at least one set ofwheels for moving the container lift vehicle in a horizontal directionon the top rail grid.

In an embodiment of the storage system, the vehicle body of thecontainer lift vehicle comprises a framework featuring internal guidesurfaces arranged to interact with the guide elements of the guideshuttle when the lifting assembly is arranged inside the vehicle body,such that the horizontal alignment of the lifting frame part isstabilised and maintained. In other words, such that horizontalmisalignment of the lifting frame part is restricted.

In an embodiment of the storage system, the container lift vehiclecomprises a first set of wheels and a second set of wheels, the firstset of wheels for moving the container lift vehicle in a first directionon the top rail grid, and the second set of wheels for moving thecontainer lift vehicle in a second direction on the top rail grid, thesecond direction being perpendicular to the first direction, and thefirst set of wheels are displaceable in a vertical direction between afirst position, wherein the first set of wheels allow movement of thecontainer lift vehicle in the first direction, and a second position,wherein the second set of wheels allow movement of the container liftvehicle in the second direction.

In an embodiment of the storage system, the internal guide surfaces arearranged in vertical planes corresponding to the vertical guide surfacesof a grid column from which a storage container is lifted. In otherwords, the internal guide surfaces are arranged to be in the samevertical planes as the corresponding vertical guide surfaces of a gridcolumn in which a storage container is to be lifted or lowered by thecontainer lift.

In an embodiment of the storage system, the container lift comprises agantry extending over at least a section of the top rail grid. Thelifting assembly or lifting device of the container lift may beconnected to the gantry, such that the lifting assembly may move in alateral direction relative to the top rail grid. The gantry may have alower level above an upper level of a container handling vehicle, suchthat the container handling vehicle may access a grid column below thegantry.

In an embodiment of the storage system, the spoolable lifting elementmay have a length greater than 6 meters, greater than 7, greater than 8meters, greater than 9 meters, or greater than 10 meters.

In an embodiment of the storage system, the container lift may comprisea spoolable lifting element having a length greater than the height ofthe storage grid.

In an embodiment, the storage system comprises two storage grids,wherein a first storage grid is arranged above a second storage grid,and the container lift is arranged to lift or raise a storage containerbetween a top rail grid of the first storage grid and the top rail gridof the second storage grid.

In an embodiment, the storage system may comprise at least one transfercolumn, extending from a bottom of the storage grid, such that thecontainer lift may raise or lower a storage container between the bottomof the storage grid and a position below the bottom of the storage grid.A transfer column extending from the bottom of a storage grid may alsobe termed a guide column. The transfer column may extend from the bottomto a container guiding assembly or a picking/supply station.

In an embodiment of the storage system, the container lift is arrangedto lift or raise a storage container between the top rail grid and aposition below a bottom, or lowest level, of the storage grid.

In a second aspect, the present invention provides a container liftvehicle for a storage system according to the first aspect, comprising

-   -   a vehicle body comprising internal vertical guide surfaces;    -   at least one set of wheels for moving the container lift vehicle        in a horizontal direction on a top rail grid; and    -   a lifting device arranged to lift a storage container from a        grid column and into the vehicle body,        wherein the lifting device comprises a lifting assembly,        comprising a lifting frame part and a guide shuttle, at least        one spoolable lifting element and at least one lifting shaft,        wherein    -   the spoolable lifting element connects the lifting shaft and the        lifting assembly, such that the lifting assembly may move in a        vertical direction by rotation of the lifting shaft,    -   the lifting frame part is for releasable connection to a storage        container, and    -   the guide shuttle is arranged above the lifting frame part and        comprises guide elements arranged to interact with the internal        vertical guide surfaces, such that the horizontal alignment of        the lifting frame part is stabilised and maintained when        accommodated inside the vehicle body.

In other words, the guide elements are arranged to interact with theinternal vertical guide surfaces, such that horizontal tilting and/orhorizontal misalignment of the lifting frame part is restricted.

The spoolable lifting element may be spooled onto the lifting shaft whenthe lifting shaft is rotated.

The lifting frame part may releasably connect to a topside of a storagecontainer. The lifting frame part may comprise gripper elements arrangedon the bottom side of the lifting frame part.

In an embodiment of the container lift vehicle, the guide shuttlecomprises four vertically extended corner sections and at least one ofthe guide elements is arranged at each corner section to interact withthe internal vertical guide surfaces of the vehicle body.

In an embodiment of the container lift vehicle, the internal verticalguide surfaces are arranged at each of four inside corners of a cavity,or internal section, of the vehicle body, in which cavity or section astorage container may be accommodated.

The container lift vehicle may comprise any of the features of thecontainer lift defined in the first aspect of the invention.

In an embodiment of the container lift vehicle, the guide elementscomprise sliding devices, roller assemblies or any combination thereof.

In an embodiment of the container lift vehicle, the roller assembliesand the sliding devices comprise at least one rotatable circumferenceand sliding surface, respectively, arranged to interact with acorresponding internal vertical guide surface of the vehicle body.

In an embodiment of the container lift vehicle, the roller assembliescomprise at least two guide wheels arranged at each corner section ofthe guide shuttle, the two guide wheels arranged to rotate inperpendicular vertical planes.

In an embodiment of the container lift vehicle, the roller assembliescomprise a first roller assembly and a second roller assembly arrangedat different levels of a corner section.

In an embodiment of the container lift vehicle, the first rollerassembly comprises a first guide wheel and a second guide wheel,arranged to rotate in a corresponding first and second vertical planebeing perpendicular to each other. Each of the first and second verticalplane may be perpendicular to corresponding internal vertical guidesurfaces with which the guide wheels may interact.

In other words, the first guide wheel and the second guide wheel arearranged to rotate in a first vertical plane and a second verticalplane, respectively, and the first vertical plane is perpendicular tothe second vertical plane.

In an embodiment of the container lift vehicle, the second rollerassembly comprises a third guide wheel and a fourth guide wheel arrangedat each corner section to rotate in a corresponding third and fourthvertical plane being perpendicular to each other, wherein the thirdvertical plane and the fourth vertical plane are coincident or parallelto the first vertical plane and the second vertical plane, respectively,and the first guide wheel and the second guide wheel are arranged at ahigher level relative to the third guide wheel and fourth guide wheel,respectively.

In a third aspect, the present invention provides a container lift for astorage system according to the first aspect, comprising

-   -   a framework comprising internal vertical guide surfaces;    -   a lifting device arranged to lift a storage container from a        grid column and into the framework,        wherein the lifting device comprises a lifting assembly,        comprising a lifting frame part and a guide shuttle, at least        one spoolable lifting element and at least one lifting shaft,        wherein    -   the spoolable lifting element connects the lifting shaft and the        lifting assembly, such that the lifting assembly may move in a        vertical direction by rotation of the lifting shaft,    -   the lifting frame part is for releasable connection to a storage        container, and        the guide shuttle is arranged above the lifting frame part and        comprises guide elements arranged to interact with the internal        vertical guide surfaces, such that the horizontal alignment of        the lifting frame part is stabilised and maintained when        accommodated inside the framework.

In an embodiment, the container lift comprises a gantry to which thelifting assembly or lifting device may be connected, such that thelifting assembly may move in a lateral direction.

The container lift may comprise any of the features of the containerlift defined in the first aspect of the invention and any of thefeatures of the container lift vehicle defined in the second aspect.

In a fourth aspect, the present invention provides a method oftransferring a storage container in a storage system according to anyembodiment of the first aspect, comprising the steps of:

-   -   moving the container lift to a position above a storage column        in which the storage container is arranged;    -   lowering the lifting assembly to releasably connect the lifting        frame part to an upper section of the storage container;    -   raising the lifting assembly and the storage container to a        level above the top rail grid;    -   moving the container lift to a position above a transfer column;        and    -   lowering the lifting assembly through the transfer column while        stabilizing the horizontal alignment of the lifting frame part        by interacting the guide elements with the four column profiles        of the transfer column.

SHORT DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described in greater detail byway of example only and with reference to the following drawings:

FIGS. 1A and 1B are perspective views of a first prior art storagesystem and a first prior art container handling vehicle.

FIGS. 2A and 2B are perspective view of a second prior art storagesystem and a second prior art container handling vehicle.

FIG. 3 is a cross-sectional view of a prior art vertical column profile.

FIG. 4 is a cross-sectional view of a prior art grid column made up offour vertical column profiles as shown in FIG. 3.

FIG. 5 is a perspective view of a third prior art storage systemfeaturing two vertically separated storage grids.

FIG. 6 are perspective views of a prior art container lift as used inthe storage system in FIG. 5.

FIG. 7 is a perspective view of a first exemplary storage systemaccording to the invention.

FIGS. 8-12 are perspective and side views of a first exemplary containerlift vehicle according to the invention.

FIGS. 13 and 14 are perspective views of a first container lift vehicleas shown in FIGS. 8-12 arranged on a storage grid.

FIGS. 15 and 16 are perspective views of a container guiding assemblyarranged between the two storage grids in FIG. 7.

FIG. 17 is a perspective view of a first exemplary guide shuttle.

FIG. 18 is a perspective view of a second exemplary guide shuttle.

FIGS. 19 and 20 are perspective views of a second exemplary storagesystem according to the invention.

FIGS. 21-23 are perspective views of the second storage system in FIGS.19 and 20 showing details of a second exemplary container lift vehicleaccording to the invention.

FIG. 24 is a perspective view of a third exemplary storage systemaccording to the invention.

FIGS. 25A-23C are views of a third exemplary container lift vehicleaccording to the invention.

FIG. 26 is a perspective view of an exemplary container guiding assemblyarranged between the two storage grids in FIG. 24.

FIG. 27 is a perspective view of a fourth exemplary storage systemaccording to the invention.

FIG. 28 is a detailed perspective view of an exemplary container lift ofthe storage system in FIG. 27.

DETAILED DESCRIPTION OF THE INVENTION

As described above in connection with the prior art storage systems inFIGS. 1,2 and 5, use of dedicated container lifts 50 are required when astorage container is to be moved vertically over more than about 6 m.

The present invention provides a container lift vehicle which allows forhighly flexible storage systems, wherein the use of dedicated containerlifts 50 are no longer required. The container lift vehicle may be usedto move a storage container over vertical distances exceeding what ispossible by the prior art container handling vehicles and may be used totransfer storage containers between two vertically separated storagegrids and/or between a raised storage grid, e.g. a storage grid on amezzanine, and a picking/supply station arranged below the storage grid.The container lift vehicle provides for a highly flexible lift system inwhich the container capacity may easily adapted by increasing orreducing the number of container lift vehicles and/or grid columnsthrough which the containers are moved, i.e. transfer columns.

In the exemplary embodiments below, the columns of the storage grids 104are only described as grid columns 112. However, as described for theprior art storage systems in FIGS. 1 and 2, grid columns 112 used forstorage of the storage containers 106 may also be termed storage columns105, while grid columns used to e.g. transfer storage containers betweena top rail grid and a picking/stocking station or between separatestorage grids may be termed transfer columns 119,120.

A first exemplary embodiment of a storage system 1 is shown in FIG. 7.The storage system features two vertically separated storage grids104′,104″, container handling vehicles 200 arranged on the top rail grid108 of each storage grid, and a container lift vehicle 2 arranged on thetop rail grid of the upper storage grid 104″. The upper storage grid isarranged on a mezzanine 80. In this embodiment, the container liftvehicle 2 is arranged to lift/raise storage containers 106 between thetop rail grid 108 of the upper storage grid 104′ and the lower storagegrid 104″. A container guiding assembly 23 is arranged between the upperand lower storage grid. The container guiding assembly 23 is arranged tointeract with the guide shuttle 19 such that tilting of the liftingframe 17 is avoided when the guide shuttle is not interacting with agrid column 112, i.e. when the guide shuttle 19 is at a position betweena lower level of the upper storage grid 104″ and the top rail grid 108of the lower storage grid 104′. Details of the container guidingassembly 23 is shown in FIGS. 15 and 16.

The container lift vehicle is shown in detail in FIGS. 8-12 and featuresa first set of wheels 32 a and a second set of wheels 32 b for movingthe container lift vehicle 2 in two perpendicular directions on the toprail grid 108. A lifting device 18 similar to that shown in FIG. 3 isarranged to lift a storage container 106 from a grid column 112 of theupper storage grid 104″ and into a cavity 25 of the vehicle body 3. Whenaccommodated in the cavity 25, the storage container 106 is at a levelabove the top rail grid 108, i.e. such that the container lift vehicle 2may move upon the top rail grid 108 while accommodating the storagecontainer.

The lifting device 18 features a lifting assembly comprising a liftingframe part 17 and a guide shuttle 19, two lifting bands 16 (i.e. twospoolable lifting elements) and a lifting shaft 20 connected to a motor8. The lifting bands 16 are connected to spools 9 on the lifting shaft20 and the lifting frame part 17, such that the lifting frame part 17will move in a vertical direction when the lifting shaft 20 rotates. Thelifting frame part 17 features connecting elements (shown as 24, FIG.17) and guiding pins 30 for releasable connection to a storage container106.

As seen in FIGS. 17, 18, the guide shuttle 19 is connected at a topsideof the lifting frame 17 part and comprises four corner sections 21. Themain function of the guide shuttle 19 is to restrict tilting of thelifting frame part 17 when lifting/lowering the lifting frame partthrough a grid column 112 of a storage grid 104, see FIGS. 13 and 14. Afurther function of the guide shuttle 19 is to ensure that the liftingframe part 17 is horizontal when arranged within the container liftvehicle 2.

The guide shuttle achieves this function through providing guidingelements that is able to engage the guide surfaces 116 of a grid column112, in particular with a transfer column 119,120, and hence guide thevertical movement of the lifting frame part 17 as it moves verticallywith the lifting frame part 17, the guiding taking place from a locationclose to or adjacent the lifting frame part 17. The guide shuttle 19 maybe connected directly to the lifting frame part 17, may be an integralpart of the lifting frame part or may be connected by an intermediarypart (or parts) which extends vertically between the guide shuttle 19and the lifting frame part 17.

In the illustrated embodiment, each corner section 21 of the guideshuttle features four guide wheels 22 a-22 d (i.e. guiding elements orroller assembly). Each guide wheel has an outer circumference havingabout the same horizontal extent as the horizontal circumference of thelifting frame part 17. In this manner, the guide wheels 22 a-22 d mayinteract with an inner guide surface 118 of the vehicle body 3 when theguide shuttle is inside the container lift vehicle 2 and interact withthe vertical guide surfaces 116 of a grid column 112 (see FIGS. 3 and 4)when moving within said grid column.

The four guide wheels feature a first pair of guide wheels 22 a, 22 b(i.e. a first roller assembly) and a second pair of guide wheels 22 c,22 d (i.e. a second roller assembly), wherein the first pair is arrangedat a level above the second pair. In each pair of guide wheels, the twowheels are arranged to rotate in two perpendicular vertical planes, i.e.their axles are arranged at 90° to each other. By having the first andsecond pair of guide wheels arranged at different levels, tilting of theguide shuttle 19, and consequently the lifting frame part 17 and anystorage container 106 connected thereto, is restricted. A detailed viewof the guide shuttle 19 is shown in FIG. 17.

An alternative embodiment of a guide shuttle 2′ is shown in FIG. 18. Inthe alternative guide shuttle, the guide wheels 22 a-22 d are replacedby a vertically extended sliding block 12 (or other arrangement ofslider, i.e. a guiding element having sliding surfaces) arranged at eachcorner section 21 of the guide shuttle 2′. The sliding blocks 12 mayrequire more frequent servicing due to wear and may not be as silentduring use as the guide shuttle having guide wheels but will provide thesame advantageous effect of restricting the tilt of the lifting frame17.

Further embodiments of a guide shuttle are envisioned. Such embodimentsmay include any combination of guiding elements, such as rollerassemblies featuring any combination of guide wheels, rotatablecylinders and rollerballs, and various types of bearing or slidingelements, such as the previously described sliding blocks. A commonfeature of the guiding elements is the provision of contact points or avertical surface area at each corner of the guide shuttle, the contactpoints or surface areas being sufficiently separated, or extended, in avertical direction to stabilize the lifting frame.

The preferred vertical distance between the contact points, or theheight of a vertical contact area, will depend on the horizontaldistance between the contact points, or the height of the contact area,and a corresponding vertical guide surface of a grid column in which theguide shuttle is moved or a corresponding inner guide surface of thecontainer lift vehicle. The vertical distance between the contactpoints, or the height of the contact area, is preferably at least 25times the horizontal distance between the contact points, or the contactarea, and a corresponding vertical guide surface or internal guidesurface. In relation to the width of the lifting frame part 17, thevertical separation of the contact points, or the vertical extent of thecontact area, may be at least 25% or at least 50% of the width of thelifting frame part.

As opposed to the prior art container handling vehicles 200,300, thelifting device 18 of the container lift vehicle is not dependent onhaving four lifting bands 16 connected to the lifting frame part 17since the horizontal positioning of the lifting frame part is ensured bythe guide shuttle 19. In the container lift vehicle shown in FIGS. 8-14only two lifting bands 16 are used.

To avoid tilting of the lifting frame part during transition between theupper storage grid 104″ and the lower storage grid 104′, the storagesystem may feature a container guiding assembly 23 as shown in FIGS. 15and 16. The container guiding assembly 23 will also allow room forretrieval of the storage container 106 by a container handling vehicle200,300 arranged on the lower storage grid 104′ after it has beentransferred from the upper storage grid 104″. The main features of thecontainer guiding assembly 23 are a support frame 13 arranged at the toprail grid 108 of the lower storage grid 104′ to support the lower endsof two grid columns 112 (or transfer columns 119/120) extending from thebottom of the upper storage grid, and two vertically moveable guidingprofiles 26, each having a recess 27 for interaction with correspondingactuatable inter-grid guiding elements 28 on the guide shuttle 19. Theguiding profiles are connected to counter weights 29 via pulleys 31,such that the guiding profiles are biased towards an upper position. Thesupport frame 13 is arranged at a height allowing access for a containerhandling vehicle below the lower ends of the two grid columns 112extending from the upper storage grid. The two extended grid columns mayalso be termed transfer columns.

To transfer a storage container 106 from the upper storage grid 104″ tothe lower storage grid 104′, the lifting frame part 17 and storagecontainer 106 are lowered from the upper storage grid via a grid column112 extending down to the container guiding assembly 23. After exitingthe lower level of the upper storage grid 104″, the inter-grid guidingelements 28 are actuated by an actuating mechanism 38 to extend beyondthe horizontal circumference of the lifting frame part 17. Theinter-grid guiding elements 28 interacts with the corresponding recesses27 of the guiding profiles 26 during the downwards movement. The guidingprofiles 26 stabilizes the guide shuttle 19 during the movement of thelifting frame part 17 and storage container 106 towards a grid column112 of the lower storage grid 104′. When the storage container has beendelivered to the lower storage grid 104′, the lifting frame part 17 islifted towards the upper storage grid 104″ and the guiding profilesfollow the movement of the guide shuttle 19 and are returned to theirupper position due to the counter-weights 29.

A second exemplary embodiment of a storage system 1 is shown in FIGS.19-21. In this embodiment, the storage system features a single storagegrid 104 arranged on a mezzanine 80 and connected via two extended gridcolumns 112′ to a picking/stocking station 109 arranged below themezzanine. Two exemplary embodiments of a container lift vehicle 2 arearranged at the top rail grid 108, details of the container liftvehicles are shown in FIGS. 22 and 23. To transfer a storage containerbetween the storage grid 104 and the picking/stocking station 109, thestorage container is lifted or lowered via the extended grid columns112′ (or transfer columns 119/120). A lower opening of the extended gridcolumns is arranged such that the guide shuttle 19 is within the gridcolumn when the storage container is at a required level within thepicking/stocking station and the lifting frame part 17 and storagecontainer are consequently prevented from tilting during the transfer.

The container lift vehicle 2′ in FIGS. 19-23 have most of its featuresin common with the container lift vehicle 2 in FIGS. 8-12, and thecommon features have the same reference numbers. The main difference isthat the container lift vehicle in FIGS. 19-23 have a single set ofwheels and are thus only able to move in a single direction upon the toprail grid. This provides for a simpler vehicle construction at the costof a somewhat less flexible lift system. Further, the container liftvehicle 2′ features a single lifting wire 15 for connecting the liftingframe part 17 and the lifting shaft instead of two lifting bands 16 asdisclosed above.

A third exemplary embodiment of a storage system 1 is shown in FIG. 24.The storage system is similar to the storage system shown in FIG. 7 andfeatures two vertically separated storage grids 104′,104″, a containerhandling vehicle 200 arranged on the top rail grid 108 of each storagegrid, and a container lift vehicle 2″ arranged on the top rail grid 108of the upper storage grid 104″. The upper storage grid is arranged on amezzanine 80. The mezzanine may also represent a second floor of abuilding in which the storage system is arranged. In the third exemplaryembodiment, the container lift vehicle 2″ has most of its features incommon with the container lift vehicle in FIGS. 19-23. However, to allowan alternative transfer of storage containers between the two storagegrids, the container lift vehicle 2″ features an extension frame 14arranged between the lifting frame part 17 and the guide shuttle 19, seeFIGS. 25A-C. The extension frame 14 allows for a simplified containerguiding assembly 23′ to allow transfer of storage containers 106 betweenthe upper and lower storage grid. The container guiding assembly 23′features a support frame 13 arranged at the top rail grid 108 of thelower storage grid 104′ to support the lower ends of two grid columns112 extending from the bottom of the upper storage grid. Grid columnsextending from the bottom of a storage grid may also be termed guidecolumns. The extension frame 14 may advantageously be higher than thecontainer handling vehicles 200 of the storage system as this allows fora height between the lower end of the extended grid column and the toprail grid of the lower storage grid which allows the container handlingvehicle access to a storage container delivered to the lower storagegrid by the container lift vehicle, see FIG. 26.

A fourth exemplary embodiment of a storage system 1 is shown in FIG. 27.The storage grid 104 have the same features as discussed above. Thefourth storage system is mainly differentiated from the storage systemsabove in that the container lift 2′″ is not arranged to move on the toprail grid 108 but features a gantry 11 along which the container liftmay move laterally above the top rail grid 108.

Details of the container lift is shown in FIG. 28. To restricthorizontal tilting of the lifting assembly (i.e. the lifting frame part17 and the guide shuttle 19) when raised above a grid column, thecontainer lift comprises a framework 10 having internal guide surfaces118 arranged to interact with the guide elements 22 c of the guideshuttle 19. The internal guide surfaces 118 will prevent a storagecontainer lifted by the lifting assembly from tilting, and possiblybecoming stuck within the grid column, when the guide shuttle is nolonger in contact with the grid column, i.e. is lifted above the toprail grid 108.

REFERENCE NUMERALS

-   1 Storage system-   2 Container lift vehicle-   3 Vehicle body-   8 Motor (for lifting shaft)-   9 Spools (for lifting bands)-   10 Framework-   11 Gantry-   12 Sliding block, sliding element, sliding device-   13 Support frame-   14 Extension frame-   15 Lifting wire-   16 Lifting band-   17 Lifting frame, lifting frame part-   18 Lifting device-   19 Guide shuttle-   20 Lifting shaft-   21 Corner section (of guide shuttle)-   22 Guide wheels-   23 Container guiding assembly-   24 Container connecting elements-   25 Cavity (for accommodating a storage container)-   26 Vertically moveable guiding profiles-   27 Recess (in vertically moveable guiding profiles)-   28 Inter-grid guiding elements-   29 Counter-weight-   30 Guiding pin-   31 Pulley-   32 a, 32 b Wheel arrangement-   38 Actuating mechanism (for inter-grid guiding elements)-   50 Storage container lift

51 Vertical guide members

-   52 Guide track-   53 Storage container shuttle-   54 Support arm-   55 Vertical guide frame-   56 Guide wheels (on vertical guide frame)-   80 Mezzanine-   100 Framework structure-   102 Upright members of framework structure, i.e. vertical column    profiles-   103 Horizontal members of framework structure-   104 Storage grid-   105 Storage column-   106 Storage container-   107 Stack-   108 Top rail grid, rail system-   109 Picking/stocking station-   110 First set of parallel rails in first direction (X), top rails-   111 Second set of parallel rails in second direction (Y), top rails-   112 Grid column-   115 Grid opening-   116 Vertical guide surface-   117 Inside corner of a grid column-   118 Inner guide surfaces (of the container lift vehicle)-   119 Transfer column,-   120 Transfer column-   122 Grid cell-   200 Prior art container handling vehicle-   201,301 Wheel arrangement-   300 Prior art container handling vehicle-   X First direction-   Y Second direction-   Z Third direction

1. A storage system comprising at least one storage grid and a containerlift, the storage grid comprises vertical column profiles defining aplurality of grid column , the grid columns comprise storage columns, inwhich storage containers can be stored one on top of another in verticalstacks, and at least one transfer column, each of the grid columns beingdefined by four vertically extending column profiles, and the columnprofiles are interconnected at their upper ends by top rails forming ahorizontal top rail grid of the storage grid, wherein the container liftcomprises: a lifting assembly which is suspended from one or morespoolable lifting elements and arranged to be raised or lowered in orderto raise or lower an accompanying storage container within the storagegrid, wherein the lifting assembly comprises a lifting frame part forreleasable attachment to an upper section of a storage container and aguide shuttle arranged to guide the lifting frame part and anyaccompanying storage container (106) as the lifting frame part is raisedand lowered within the storage grid, the guide shuttle is arranged abovethe lifting frame part and comprises guide elements which are eacharranged to interact with one of the four column profiles of a gridcolumn to stabilise and maintain horizontal alignment of the liftingframe part and any accompanying storage container during the raisingand/or lowering of the lifting frame part; and a framework featuringinternal guide surfaces arranged to interact with the guide elements ofthe guide shuttle when the guide shuttle is at a level above the toprail grid, such that the horizontal alignment of the lifting frame partis stabilised and maintained.
 2. A storage system according to claim 1,wherein the guide elements comprise sliding devices, roller assembliesor any combination thereof.
 3. A storage system according to claim 1,wherein the guide shuttle is arranged above the lifting frame part.
 4. Astorage system according to claim 1, wherein each column profile of agrid column comprises two vertical guide surfaces forming an insidecorner of the grid column, and each guide element is arranged tointeract with at least one of the vertical guide surfaces of acorresponding inner corner of a grid column in which the liftingassembly is moved.
 5. A storage system according to claim 4, wherein atleast one of the guide elements comprises a roller assembly having atleast one rotatable circumference arranged to interact with acorresponding vertical guide surface of a grid column in which thelifting assembly is moved.
 6. A storage system according to claim 5,wherein the roller assembly comprises at least one rotatablecircumference arranged to interact with the vertical guide surfaces of acorresponding inside corner of a grid column in which the lifting frameis moved.
 7. A storage system according to claim 1, wherein the guideshuttle comprises four vertically extended corner sections, wherein atleast one guide element is arranged at each corner section.
 8. A storagesystem according to claim 1, wherein the container lift is a containerlift vehicle comprising a vehicle body, into which a storage containermay be lifted by the lifting assembly, and at least one set of wheelsfor moving the container lift vehicle in a horizontal direction on thetop rail grid.
 9. A storage system according to claim 8, wherein thevehicle body comprises a framework featuring internal guide surfacesarranged to interact with the guide elements of the guide shuttle whenthe lifting assembly is arranged inside the vehicle body, such that thehorizontal alignment of the lifting frame part is stabilised andmaintained.
 10. A storage system according to claim 1, wherein the innerguide surfaces are arranged in vertical planes corresponding to thevertical guide surfaces f a grid column from which a storage containeris lifted.
 11. A storage system according to claim 1, wherein thecontainer lift comprises a gantry extending over at least a section ofthe top rail grid.
 12. A container lift vehicle for a storage systemaccording to claim 1, comprising: a vehicle body comprising internalvertical guide surfaces; at least one set of wheels for moving thecontainer lift vehicle in a horizontal direction on a top rail grid; anda lifting device arranged to lift a storage container from a grid columnand into the vehicle body, wherein the lifting device comprises alifting assembly, comprising a lifting frame part and a guide shuttle,at least one spoolable lifting element and at least one lifting shaft,wherein wherein the spoolable lifting element connects the lifting shaftand the lifting assembly, such that the lifting assembly may move in avertical direction by rotation of the lifting shaft, wherein the liftingframe part is for releasable connection to a storage container, andwherein the guide shuttle is arranged above the lifting frame part andcomprises guide elements arranged to interact with the internal verticalguide surfaces, such that the horizontal alignment of the lifting framepart is stabilised and maintained.
 13. A container lift vehicleaccording to claim 12, wherein the guide shuttle comprises fourvertically extended corner sections and at least one of the guideelements arranged at each corner section, wherein the guide elements arearranged to interact with inner vertical guide surfaces of the vehiclebody, such that the guide shuttle and the lifting frame part arerestricted from tilting relative a horizontal plane when the guideshuttle is inside the vehicle body.
 14. A container lift vehicleaccording to claim 12, wherein the guide elements comprise slidingdevices, roller assemblies or any combination thereof.
 15. A containerlift vehicle according to claim 14, wherein the roller assemblies andthe sliding devices comprise at least one rotatable circumference orsliding surface, respectively, arranged to interact with a correspondinginner vertical guide surface of the vehicle body.
 16. A method oftransferring a storage container in a storage system according to claim1, comprising the steps of: moving the container lift to a positionabove a storage column in which the storage container is arranged;lowering the lifting assembly to releasably connect the lifting framepart to an upper section of the storage container; raising the liftingassembly and the storage container to a level above the top rail grid;moving the container lift to a position above a transfer column; andlowering the lifting assembly via the transfer column while stabilizingthe horizontal alignment of the lifting frame part by interacting theguide elements with the four column profiles of the transfer column.